This file as documentation (which seems lacking) states is used for calling custom Maven goals from the IDE.
Ignoring this file was a source much confusion in few projects (mapping Run action to custom goals... etc etc) 
Also this file does anything worth ignoring
Added by #145
Exclusion of `nbactions.xml`  from `.gitgnore` should be discussed.

Add eslint cache ignore for node projects.

Add hidden virtualenv to Python template

Ignore GNU Global GSYMS database of other symbols

Update ignore for fastlane files in Objective-C

ignore HTF test framework artifact directory

Updated for Joomla 3.6.2

Exclude folder for CodeRush settings

See http://hackage.haskell.org/package/HTF-0.13.1.0/docs/Test-Framework-CmdlineOptions.html (opts_historyFile)

Remove config/secrets.yml

Rails no longer generates this file with sensitive secrets (default now is to do `secret_key_base: <%= ENV["SECRET_KEY_BASE"] %>` in production).

Update Visual Studio Code to support workspace files.

Visual Studio Code has a few files that can be placed into the workspace
in order to share settings across users.  Settings.json is for project
specific overrides.  Tasks.json is for executable tasks (build, gulp, etc.)
While launch.json is for debugging specific tasks.

Ignore elm-stuff project-wide

Adding index.html files for cache and upload folders

index.html should be in the upload and cache folders in order to avoid direct access

Scala: Ignore ENSIME files

Correct .jar and .class mentions

Add "*.out" to Go.gitignore

Ignore terraform module directory

See <https://www.terraform.io/docs/commands/get.html>

Added project folder created by Consulo IDE to Unity.gitignore

Added gregoriotex

See documentation at
https://github.com/gregorio-project/gregorio

Fix indentation 'Code Injection'

ignore busy indicator of uncompressed .synctex file

Add *.wrt produced by scrwfile

Ignore .pdf

On Windows, when PDF is opened with Acrobat Reader, one gets following output:

    ! I can't write on file `document.pdf'.
    Please type another file name for output:

If one simply presses "Enter" to continue, the file `.pdf` is generated. Since this is a common case and `.pdf` is never used as full file name, this file should be ignored, too.